This implements the code for row-by-row filter selection but does not provide an
actual implementation; the selection function just chooses the lowest set filter
bit.
Signed-off-by: John Bowler <jbowler@acm.org>
A debug() assert fired if windowBits was set to 8 for the Huffman only and
no-compression cases. This commit changes it to do some extra checking. Remove
unreachable code in pz_default_settings, eliminate a spurious warning in pngcp
for small files.
Signed-off-by: John Bowler <jbowler@acm.org>
Implemented better defaulting of zlib settings based on image properties.
Implemented pass-through of png_write_rows when the rows can be used directly (a
common case) optimizing the handling of previous-row buffering.
Removed the METHODICAL filter selection method and disabled the HEURISTIC one;
the first was ridiculously slow (though useful for experiments) the second
doesn't work. Filter selection is temporarily disabled (it defaults to the
lowest numbered filter in the list; typically 'none').
New handling of compression settings (incomplete), new PNG compression level
(not yet visible in an API).
Back ported 'PNG_FAST_FILTERS' from 1.6 (in png.h).
There are minimal API changes beyond removal of the selection options. Work is
still to be done to investigate a filter selection mechanism that is at least as
good as the previous one.
Signed-off-by: John Bowler <jbowler@acm.org>
More sophisticated defaulting which helps significantly for some files along
with code to make it easier to control the compression defaults and to make the
settings honor the API calls the application makes (previously low windowBits
settings would get reset to higher values.)
Signed-off-by: John Bowler <jbowler@acm.org>
png_set_compression_buffer_size would result in a spurious debug assert if the
compression buffer size was set to something other than a multiple of
PNG_ROW_BUFFER_SIZE; the debug test failed to add the buffer 'start'
Signed-off-by: John Bowler <jbowler@acm.org>
There are two separate problems. The first is that the CMINFO optimization code
gets run twice on any PNG IDAT stream longer than 2048 bytes and the second time
can overwrite bytes 2048,2049 destroying the output.
The second is that one of the (debug) checks was slightly wrong (< when <=
should have been used) and this causes write to abort maybe 1/2048 times.
Signed-off-by: John Bowler <jbowler@acm.org>
The handling of tIME and text chunks on read now records the location of the
chunks relative to PLTE and IDAT. Behavior on write is unchanged except that if
the position was recorded on read it will be re-used.
This involves an ABI change to the png_text_struct; a one byte location field is
added (with the same meaning as the one used to record unknown chunk location.)
Because this field is only used on read there is no API change unless a png_info
from a libpng read is passed to a subsequent libpng write (this did not work
very well before 1.7; the tIME chunk could get duplicated.)
png_set_text ignores the new field, resetting it to the current position in the
read or write stream. On write the position is set to the next location to be
written unless the write has not started (the position is before the signature)
in which case the location is set to PNG_HAVE_PLTE|PNG_AFTER_IDAT. When the
chunk is written the position is set to the actual write location (effectively
the position is frozen.)
Signed-off-by: John Bowler <jbowler@acm.org>
This seems safer; in fact a NULL dereference never happens because the test ends
up just doing arithmetic on NULL but it seems possible that the undefined
arithmetic can still happen if there is a bug elsewhere.
Signed-off-by: John Bowler <jbowler@acm.org>
Undefined behaviour sanitizer currently fires for this test
with an error about member access within null pointer to
struct; put the check that relies on pz->list being non-NULL
second.
Also add an example program, pngcp.c, which illustrates the problem when used to
copy pngtest.png (the result is an invalid PNG because the tIME chunk is
duplicated.)
Signed-off-by: John Bowler <jbowler@acm.org>
This rewrites the code used previously in the heuristics to make it easier to
debug and introduces the 'methodical' method, which is intended to be an
expensive but reliable way of reducing image size.
The code in this commit does not work; the 'methodical' test for success does
not take account of data buffered inside zlib and, anyway, it changes the
results of pngtest so that the test fails. This commit is just a checkpoint of
the current state; another commit will temporarily disable the 'methodical'
code.
Signed-off-by: John Bowler <jbowler@acm.org>
The filter selection options are made more intuitive (IMO, but I am not an
Intuitive User). Dummy code added for methodical filter selection.
Signed-off-by: John Bowler <jbowler@acm.org>
This implements the heuristic part of filter selction, the methodic testing
approach is still not implemented. png_set_option methods are incomplete.
Signed-off-by: John Bowler <jbowler@acm.org>
This removes the side-effect on the png_struct palette of calling png_set_PLTE
or png_set_tRNS. NOTE: this is a quiet API change, it was possible before to
alter the palette on a PNG image by using png_set_PLTE, but this was unintended
and inconsistent with the other png_set APIs.
Fix a bug in palette index checking; png_struct::num_palette could, in
principle, get changed by the transformations (e.g. png_set_quantize) and this
would invalidate the check. The palette checking init function now makes a copy
of png_struct::num_palette.
Fix a bug in pngvalid error handling. A png_error in png_write_info is not
continuable (a valid image cannot necessarily be written afterward) because the
png_error aborts the write of subsequent pre-IDAT chunks. In particular an
abort as a result of a bogus colorspace information (gAMA, cHRM, sBIT etc)
prevents the write of the PLTE chunk.
Signed-off-by: John Bowler <jbowler@acm.org>
Unify the compression code so that inflate calls are localized to a common
routine. Ground work for filter selection support. Minor API changes to use
void* not byte* for data parameters. Unification of some of the compression
code with the decompression code; IDAT_size replaces IDAT_read_size and
zbuffer_size, IDAT reading and writing is no longer controlled by the size of
the compression buffer.
Signed-off-by: John Bowler <jbowler@acm.org>
This commit moves code round and changes the filter write interfaces that took
png_uint_32 buffer pixel counts to unsigned int. Also moves compression code
and definitions into pngwutil.c so that the compression code is isolated from
other definitions.
Signed-off-by: John Bowler <jbowler@acm.org>
Improve pngvalid coverage of filter combinations, remove the (new in 1.7) code
which disabled previous-row filters on the first row of an image in some cases.
Signed-off-by: John Bowler <jbowler@acm.org>
The code failed to zero out the row buffer at the start of a pass where the AVG
filter is used because 'row_number' is not always zero (on interlaced images)
and, apparently, the assertion that the buffer had been zeroed when allocated
was not always correct for non-interlaced images. Revealed by pngvalid --size
with a hack to make it always use AVG.
Signed-off-by: John Bowler <jbowler@acm.org>
commit fc4b42b1d56f95efeb1b9fe42dc35b7d98d246bb
Merge: 74516c7 9eb1413
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 22 19:37:54 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 74516c7257f1a28a69985684c5673caa390c700a
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 22 19:32:43 2015 -0800
Make check full pass on gcc/g++ x86_64
Signed-off-by: John Bowler <jbowler@acm.org>
commit e891e34737fc0bc9ee873a5d56b83c1e777b990c
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 22 12:01:37 2015 -0800
Checkpoint: write buffering changes
This version fails in pngvalid --size because of an error handling very narrow
images, otherwise a standard build passes make check.
Signed-off-by: John Bowler <jbowler@acm.org>
commit 457a046ebdab737eefb477126cf855e49df6de50
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 22 06:39:36 2015 -0800
Fix previous bad merge
commit b4f426c97267317637d43f41fe0b05d1659bc63d
Merge: 07b9b90 a3458a6
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 22 06:32:34 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 07b9b90dfd653b744dbc3710b096facf6b4605f6
Merge: ed43306 5592e0b
Author: John Bowler <jbowler@acm.org>
Date: Sat Nov 21 17:07:23 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit ed43306599f7039a90187862db82273fca3a4c3d
Merge: 772aed7 d3c0359
Author: John Bowler <jbowler@acm.org>
Date: Tue Nov 17 17:47:26 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 772aed72378df9c8fccc5a4594b095d02d410a9c
Merge: 73ae431 801608f
Author: John Bowler <jbowler@acm.org>
Date: Mon Nov 16 14:26:38 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 73ae4316cb6db7d7f6756583a1c213c35ca4e3f4
Merge: 687e6e3 c09b3ab
Author: John Bowler <jbowler@acm.org>
Date: Sun Nov 15 09:31:30 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 687e6e393e9d0220c2a12ec474aa01b83c5e9f25
Merge: fedd6da e916d9b
Author: John Bowler <jbowler@acm.org>
Date: Thu Nov 5 08:45:14 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit fedd6da8798a14b2e002b0bc1379f5a09a03598a
Merge: 2e2fc5f ea41fd2
Author: John Bowler <jbowler@acm.org>
Date: Tue Nov 3 21:05:01 2015 -0800
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 2e2fc5f6d7678b710c52b7ea081ac4add677d8d5
Merge: 990d5f8 5b05197
Author: John Bowler <jbowler@acm.org>
Date: Mon Oct 12 08:28:30 2015 -0700
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 990d5f88688635dc0888657b689e30ffe7e7a7b3
Author: John Bowler <jbowler@acm.org>
Date: Sun Oct 4 17:04:53 2015 -0700
Read row buffer changes
The read code now allocates one row buffer of the size of the input PNG row and,
only if required, one buffer of the size of the output.
The output buffer is required for the progressive reader (always) and for the
sequential reader if libpng is de-interlacing an image (because the output row
is used multiple times if png_read_row is called with a display row parameter.)
This should reduce memory utilization by libpng significantly, but it has no
detectable effect on overall performance figures of the test programs, these are
probably dominated by memory allocations for the whole image within the test
programs.
Signed-off-by: John Bowler <jbowler@acm.org>
commit 527bf989bf0e30440f9e07a5544a6ebb1d6fd039
Merge: 50ebbc2 9099254
Author: John Bowler <jbowler@acm.org>
Date: Sat Oct 3 13:39:17 2015 -0700
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 50ebbc2c9a24cf1a6b428db53d55fbd5af4d6be6
Merge: 21a7f40 2cd6d56
Author: John Bowler <jbowler@acm.org>
Date: Sat Oct 3 11:16:32 2015 -0700
Merge branch 'libpng17' into libpng17-filter-enhancements
commit 21a7f401ab40c79ead9e35882a8066e2cf1d6902
Merge: b512e1c 15a143e
Author: John Bowler <jbowler@acm.org>
Date: Wed Sep 30 19:01:23 2015 -0700
Merge branch 'libpng17' into libpng17-filter-enhancements
commit b512e1c2c5bfe6df8b6dca32f862d325ec22115e
Author: John Bowler <jbowler@acm.org>
Date: Wed Sep 30 17:33:34 2015 -0700
Transform rewrite: perform transforms in small chunks
The intent of this change is to reduce the memory footprint during transform
sequences by performing transforms in fixed (small) sized blocks of pixels.
The change is incomplete; the filter code still works row-by-row, so the whole
tranform also works row-by-row, the intent is to fix this so that everything
works in small(ish) chunks.
At present the change has no discernable effect on pngvalid --speed or pngstest
with (e.g.) rgb-8-1.8.png; user time and (minor) page faults are the same in old
and new versions. The same applies to real-world 15MP PNG images; even on these
the presence of the filter code causes a cyclical progress through memory which
will interfere with any caching otherwise possible (useful word, 'otherwise'.)
Signed-off-by: John Bowler <jbowler@acm.org>
commit 781cb3699b92beb0e6bc5e03cef8fba820267082
Author: John Bowler <jbowler@acm.org>
Date: Wed Sep 30 17:12:53 2015 -0700
Fix NO_WRITE_INTERLACE in pngvalid.c
The support for writing interlaced images directly from libpng 1.7 was
unintentionally disabled (INTERLACE_LAST was defined incorrectly, excluding the
interlaced images). This obscured the fact that the transform and error test
case generators lacked the support for writing interlaced images from libpng.
Signed-off-by: John Bowler <jbowler@acm.org>
commit 406ee2fd7946a384f1d7713712dc646080c5c52c
Author: John Bowler <jbowler@acm.org>
Date: Wed Sep 30 17:11:40 2015 -0700
Add pngvalid --transform --interlace test
This increases code coverage by generating test cases with smaller length rows
as a result of the interlacing. Without this packswap handling was incompletely
tested.
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: John Bowler <jbowler@acm.org>
This fixes the code that optimizes RGB to Gray transformations that only
selected on channel and clarifies the handling of max_depth in the transform
code. It eliminates some UNTESTED cases and removes the write 'invert alpha'
UNTESTED macro because, while there are no test cases for it, code review
some months after writing it suggests it is ok.
Signed-off-by: John Bowler <jbowler@acm.org>
This implements a new chunk parse implementation that can be shared, it
is currently shared by the progressive reader and the sequential one
(not, yet, the writer).
The patch also implements shared transform handling that is used
throughout.
Signed-off-by: John Bowler <jbowler@acm.org>
pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
would only work with iTXt chunks with length 255 or less.
Fixed cexcept.h in which GCC 5 reported that one of the auto
variables in the Try macro needs to be volatile to prevent value
being lost over the setjmp, and fixed g++ build breaks (John Bowler).
compiled library size. It never worked properly and as far as we can
tell, no one uses it. The png_set_filter_heuristics() and
png_set_filter_heuristics_fixed() APIs are retained but deprecated.
internal struct (png_transform_control) to replace row_info and uses
that to implement affirms correctly. The change also adds checks on
the rowbytes calculation and additional checks on most transform
implementations.
Added png_uint_16 range checking, pngvalid tRNS, fixed png_uint_16:
review of previous checks, removal of some where SAFE. pngvalid: add
testing of tRNS for better code coverage pngvalid: correct rgb-to-gray
error calculations. Code coverage is still incomplete: see /*UNTESTED*/
in pngrtran.c
added RELEASE/!RELEASE convenience macros. png_muldiv_warn was used in
only one place, and the overflow condition is a genuine warning not
an internal error. Four macros allow code or function parameters to be
condition on RELEASE (or not) builds and tidy up the #ifdef handling of
functions.
where the code depended on the build base type and can be defined on
the command line, allowing testing in beta builds. Overflows previously
handled by png_warning in png.c have been changed to use new
macros/affirm functions so that beta builds will abort on overflow and
release builds will quietly ignore it. This avoids release builds
producing warnings that are of no use to end users.
Added 'assert' based overflow checking for debug builds for char
and short assignments. Simply ignore the error in release builds
(a truncated value will be used without warning). Controlled by
PNG_RANGE_CHECK_SUPPORTED.
